Pirelli 2013

[turbof1]

More interesting is the fact that Hembrey is blaming track debris for the delaminations. Does he expect all tracks to be perfectly clean at all times?

By debris,does he mean the sea of marbles and the whole chunks of rubber from his companys ridiculous tyres???

No, he means normal debris that would normally cause an instantaneous, catastrophic puncture. His assertion is that on last years tyre, the tyre would have punctured half a lap earlier, when the car ran over the debris. On this year's car, the tred gets sliced in half, but the tyre does not puncture due to the steel belt. Then, half way round the lap, the tyre reaches a critical temperature due to the damage, and the tred fails, causing a delamination.

His assertion is that the only reason we're complaining is that we're not seeing the debris strike and the puncture together (or even at all in the case of the debris strike), and hence they look like sudden, arbitrary, catarstrophic delaminations, rather than punctures.

It might be perception, but I think we had on the last 2 weekends (Bahrain, Barcelona) more tyre failures then any other 2 weekend period last year.

Also, Alonso had a slow puncture, but his tyre did not got to the critical temperature. How come not?

[Pup]

Reading the Pirelli release, it is not the construction that is being altered, it is only the compounds. The cars, including MP24-28 were designed around a stiffer construction. Altering the construction now, would be a mad thing to do.

Nonetheless...

“We’re going to give teams a lot more data tomorrow. We’re finalising the precise specification. Really, it’s a little bit of a mix of what we’ve been using this season and some of the structural stuff we had last season – which will help minimise the impact for the teams.

As you can imagine, there’s a lot of work to be done on aerodynamics and tyres can impact on that – the way they deform – so teams will be keen to have that data asap so they can all start working towards Canada. From an aero point of view, that can have an impact. That’s why we’d like to give them something that they’ve used a little bit in the past – so they’ve already got some data.

It’s also probably as well the way the compounds will work with the car: they’ll be less aggressive from some points of view which will slightly modify the strategy of how they use the tyres during the race.”

[turbof1]

So in any case the tyres will deflect more like they did in 2012. Teams do have a full year of data about that. Implementing it will be the b word though; many teams have changed their suspension, following Red Bull in their suspension geometry. Mclaren has the added bad luck it both changed from front push rod to front pull rod, and at the back rearranged the wishbones to copy Red Bull's shrouded driveshaft.

Also mind that even though they got their aero wrong due more different deflecting tyres then expected, their woes will not just go away. They developed their car with 60% scale 2013 tyres which represented the deflecting of the tyres they currently are on. The car is NOT designed for the deflection seen in 2012.

[Pup]

On this year's car, the tred gets sliced in half, but the tyre does not puncture due to the steel belt.

I may be wrong, but is the belt not made of Kevlar?

Not any more – this changed this season – it's now made of steel, which is why the debris is not puncturing it instantly.

And now back to kevlar...

The 2013 tyres have a different construction from the 2012 products, with a steel belt inside the tyre in place of last year’s kevlar belt. It is likely that this decision will be reversed with the revised tyres, as Pirelli moves back to a proven solution.

The weakness of the 2012 tyres was wear; typically the inside shoulder of the tyres would wear out and teams would run the tyre until there was no rubber left on the shoulder and then make a pit stop. However the teams understood how to manage them quite well by the end of the season.

For 2013 Pirelli tried to fix the wear problem by getting the contact patch of the tyre more reasonably positioned, but it seems that in changing the construction to achieve this they have gone too far.

[turbof1]

Why was the kevlar belt replaced by a steel one in the first place?

[Pup]

See the quote below from James Allen. Essentially they were trying to even the wear across the tire instead of having the shoulders wear faster.

[Holm86]

Why was the kevlar belt replaced by a steel one in the first place?

Something to do with the stiffness of the tire.

[turbof1]

See the quote below from James Allen. Essentially they were trying to even the wear across the tire instead of having the shoulders wear faster.

I am actually more asking to the properities of the used material: is steel perhaps bending more then kevlar to keep the contact patch better?

EDIT: thanks Holm

[Holm86]

See the quote below from James Allen. Essentially they were trying to even the wear across the tire instead of having the shoulders wear faster.

I am actually more asking to the properities of the used material: is steel perhaps bending more then kevlar to keep the contact patch better?

EDIT: thanks Holm

"Pirelli have worked with the FIA and the teams to change the tyres for 2013. This will result in a more balanced set of tyres and similar high rates of degradation as we saw at the start of last year. To achieve this Pirelli have completely redesigned the tyre range. They have softened the stiffness of the sidewalls of the tyres, but stiffened the shoulders of the tyres. The softer sidewall will induce more heat in the tyre and generally softer compounds will heat up more quickly, produce more grip, and ultimately degrade quicker than before. The stronger tyre shoulder will help keep the more flexible tyre together during a stint. Teams will be forced by this degradation into more than stop per race, also the pair of compounds at each race will ensure one set of tyres will produce far different lap times to the other (at least 0.5s per lap).
Teams and drivers will have to adapt quickly to the new balance, grip and wear levels, meaning flexibility in the cars set up will be important so some mechanical part of the car will need to have scope for greater adjustability."

This is a quote of Scarbs F1 from his preview of the 2013 season.

[strad]

Also rich language that would normally be seen as an inappropriate can occasionally be appropriate, especially when the moderator agrees

Speaks volumes Richard.
I don't think Pirelli gave any thought to diffusers.

[Richard]

Indeed it does speak volumes. Things must be really bad with Pirelli for me to deem Cam's language objective!

With regard to the topic, it strikes me that the issue seems to be tolerance for peak temperature and stress.

The number of pistops is the same as before despite Rb protestations. So to my mind that says the wear rate or tolerance of abrasion isn't too bad.

So I guess the need is for a tyre more tolerant of extreme heat and temperature that wears away at the same rate. I do appreciate this is horribly simplistic and its not as simple as changing some numbers into the recipe of a magic tyre machine. For example Coulthard reminded us that Bridgstone had a time when tyre performance went off early in the stint and they had to be nursed for a phase, but once they'd been on for a few laps (haw many?) they would regain the normal performance. The problem with Pirelli is that they need to be nursed at all times to avoid a spike in temperature.

They're a bit like Brie - it needs to warm to be perfect, but touch too warm leads to an irrecoverable mess. However no sane person could liken Brie with excreta.

[bhall]

[...]
However no sane person could liken Brie with excreta.

Meh, I could. Then again, I'm not sane.

[...]
I don't think Pirelli gave any thought to diffusers.

I don't think Pirelli gave any thought to tires.

[raymondu999]

[youtube]http://www.youtube.com/watch?v=pXSrILQbNnw[/youtube]

[Sombrero]

Pirelli, the tyre and rubbish company...

[WhiteBlue]

So I guess the need is for a tyre more tolerant of extreme heat and temperature that wears away at the same rate.

I don't think that is the right analysis. The energy balance of the tyres got affected by making the shoulder softer and generating more heat much easier. That is the root cause of the fragile tyres. Those teams that manage the 2013 tyres best like Lotus are very carefully avoiding any contribution to dissipate work into the tyre shoulder simplistically explained by a soft suspension that makes the tyre work a lot less. Those like Red Bull have too little scope for suspension softening because their aerodynamic concept requires very small tolerances in rake and ride height. At least that seems like a sensible explanation to me.

If it were just a case of making compounds more heat resistant I'm sure Pirelli could come up with a solution. But the problem is the excess of heat dissipation in the shoulders and that will not go away unless they make a fundamental change to the construction.

The second point is the steel band instead of the Kevlar reinforcement. I think the idea was good but the image it creates of Pirelli is detrimental. They will abandon this idea simply for marketing and image reasons. It actually reminds me of the Michelin problems in Indianapolis 2005. They also added a steel belt and the tyre shoulder ruptures under dynamic loads. My personal view is that Michelin had a problem with hitting a resonance frequency which is probably the worst problem you can have. It shows that you have to be extremely careful when you modify the spring and damper properties of the tyres. They are integral to the suspension properties and teams rely on the tyre manufacturer to be very consistent and conservative with the safety.

Generally I think that Pirelli does too much messing around with the tyres in order to generate publicity.